Low gloss polyester coating powder compositions

Abstract

Low gloss in a coating derived from a polyester/triglycidyl isocyanurate coating powder is achieved by including in the coating powder ethylene/acrylic acid copolymer plus a zinc salt of a fatty acid and/or a zinc salt of a beta diketone.

What is claimed is:  
     
       1. In a powder coating composition comprising a polyester resin and triglycidyl isocyanurate, the improvement wherein said coating powder composition further consists essentially of between about 2 and about 10 parts per hundred resin by weight of a copolymer of ethylene and acrylic acid, said copolymer consisting essentially of between about 80 and about 95 wt % ethylene and between about 5 and 20 wt % acrylic acid; plus a zinc salt selected from the group consisting of zinc salts of fatty acids having between 8 and 25 carbon atoms, zinc salts of α,γ-diones having between 5 and 20 carbon atoms, and mixtures thereof, with the proviso that said zinc salt is not a zinc salt of 2-mercapto benzothiazole; said zinc salt providing zinc at between about 0.05 and about 0.30 phr, whereby reduced gloss is achieved. 
     
     
       2. The coating powder composition according to  claim 1  wherein said zinc salt comprises zinc neodecanate. 
     
     
       3. The coating powder composition according to  claim 1  wherein said zinc salt comprises zinc stearate. 
     
     
       4. The coating powder composition according to  claim 1  wherein said zinc salt comprises zinc acetylacetonate. 
     
     
       5. The coating powder composition according to  claim 1  wherein said ethylene/acrylic acid copolymer has a melt index (MI 2 ) as measured by ASTM D-1238 of between about 10 and about 30.